Dose verification of constant dose rate-volumetric modulated arc therapy plan based on Varian 23EX accelerator via Portal Dosimetry(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第10期
- Page:
- 1134-1138
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Dose verification of constant dose rate-volumetric modulated arc therapy plan based on Varian 23EX accelerator via Portal Dosimetry
- Author(s):
- WANG Jie1; SHAO Kainan2; CHEN Peng1; ZENG Rong1; JIANG Qi1; ZHENG Shiming2; MIN Xuhong1
- 1. Department of Radiation Oncology, Anhui Chest Hospital, Hefei 230022, China; 2. Department of Radiation Physics, Zhejiang Cancer Hospital, Hangzhou 310022, China
- Keywords:
- ; accelerator; constant dose rate; volumetric modulated arc therapy; electronic portal imaging device; dose verification
- PACS:
- R811.1；R312
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.10.004
- Abstract:
- Abstract: Objective To verify and comparatively analyze the doses of constant dose rate-volumetric modulated arc therapy (CDR-VMAT) plan based on Varian 23EX accelerator using Varian Portal Dosimetry system and ScandiDos Delta4 three-dimensional semiconductor array. Methods RayStation treatment planning system was used to design CDR-VMAT plans based on Varian 23EX accelerator for randomly selected 10 head and neck cancer patients, 10 chest cancer patients and 10 abdominal cancer patients. Radiation fields were designed according to tumor location, and 6 MV X ray was adopted. The constant dose rate of each arc and constant gantry speed were optimized by treatment planning system. Every CDR-VMAT plan was used to generate two verification plans, with one for Portal Dosimetry system of electronic portal imaging device of 23EX and the other for Delta4 chamber array detector. Gamma passing rate was analyzed based on the criteria of 3 mm DTA and 3% Dose, and the results were analyzed with paired t test. Results For 10 cases of head and neck cancer, the Gamma passing rates of CDR-VMAT plan verified with Portal Dosimetry system and Delta4 were (97.9±1.1)% and (99.9±0.2)%, respectively (P<0.05). For 10 cases of chest cancer, the Gamma passing rates were (99.5±0.7)% and (99.7±0.4)%, respectively (P=0.09). For 10 cases of abdominal cancer, the Gamma pass rates were (99.5±0.3)% and (99.7±0.4)%, respectively (P=0.19). Conclusion CDR-VMAT as an additional radiotherapy option for Varian 23EX accelerator can effectively improve delivery efficiency. The combination of CDR-VMAT and Varian Portal Dosimetry system can easily achieve the verification of CDR-VMAT plan based on 23EX accelerator. The comparative analysis on Gamma passing rates show that both the Gamma passing rates of CDR-VMAT plans for chest cancer and abdominal cancer are higher than 95%, without statistical differences, while there is difference in Gamma passing rate of CDR-VMAT plans for head and neck cancer, but both the Gamma passing rates are still above 95%, satisfying clinical requirements
Last Update: 2019-10-29